Method for manufacturing slurry for positive electrode of nonaqueous electrolyte secondary battery and slurry for positive electrode of nonaqueous electrolyte secondary battery

Abstract

Provided is a method for manufacturing a slurry for a positive electrode of a nonaqueous electrolyte secondary battery containing an alkali metal complex oxide, the method making it possible to reliably deaerate surplus carbonic acid gas after an alkali component of a slurry containing the alkali metal complex oxide is neutralized within a short period of time. The method for manufacturing a slurry for a positive electrode of a nonaqueous electrolyte secondary battery includes a step of manufacturing an electrode slurry including a step of performing a neutralization treatment on an alkali component in the slurry by using inorganic carbon dissolved in a solvent of the slurry and a step of deaerating the inorganic carbon in the slurry as carbonic acid gas by causing cavitation.

What is claimed is: 
     
       1. A method for manufacturing a slurry, the method comprising:
 performing, by a dispersing and mixing apparatus, a dispersing and mixing step of dispersing and mixing a powder and a solvent to generate a preliminary slurry that comprises a positive electrode active material; 
 performing, by the dispersing and mixing apparatus after the dispersing and mixing apparatus performs the dispersing and mixing step, a neutralizing step of producing a primary neutralized slurry by neutralizing the preliminary slurry; and 
 performing, by the dispersing and mixing apparatus after the dispersing and mixing apparatus performs the neutralizing step, a deaerating step of producing a secondary neutralized slurry by deaerating the primary neutralized slurry, 
 wherein the deaerating step comprises applying, to the primary neutralized slurry, a shearing force in a manner that causes cavitation. 
 
     
     
       2. The method according to  claim 1 , wherein water is used as the solvent. 
     
     
       3. The method according to  claim 1 , wherein the neutralizing step comprises adding carbonic acid gas to the preliminary slurry. 
     
     
       4. The method according to  claim 3 , wherein the carbonic acid gas in the solvent is used to generate an inorganic carbon in the solvent. 
     
     
       5. The method according to  claim 3 , wherein a pressure of the carbonic acid gas is equal to or higher than 0.12 MPa and equal to or lower than 100 MPa. 
     
     
       6. The method according to  claim 3 , wherein a pressure of the carbonic acid gas is equal to or higher than 0.2 MPa and equal to or lower than 50 MPa. 
     
     
       7. The method according to  claim 3 , wherein a pressure of the carbonic acid gas is equal to or higher than 0.3 MPa and equal to or lower than 10 MPa. 
     
     
       8. The method according to  claim 3 , wherein the deaerating step comprises causing, by the dispersing and mixing apparatus, cavitation to deaerate an inorganic carbon in the primary neutralized slurry. 
     
     
       9. The method according to  claim 1 , wherein the secondary neutralized slurry is for a positive electrode of a nonaqueous electrolyte secondary battery. 
     
     
       10. The method according to  claim 9 , wherein the nonaqueous electrolyte secondary battery comprises an alkali metal complex oxide. 
     
     
       11. The method according to  claim 10 , wherein the alkali metal complex oxide is a lithium complex oxide. 
     
     
       12. The method according to  claim 1 , wherein the preliminary slurry further comprises a binder and a conductive material. 
     
     
       13. The method according to  claim 12 , wherein with respect to a total amount of the positive electrode active material, the binder, and the conductive material:
 an amount of the positive electrode active material is 60% to 99% by mass, 
 an amount of the binder is 0.1% to 25% by mass, and 
 an amount of the conductive material is 0.1% to 10% by mass. 
 
     
     
       14. The method according to  claim 12 , wherein with respect to a total amount of the positive electrode active material, the binder, and the conductive material:
 an amount of the positive electrode active material is 80% to 95% by mass, 
 an amount of the binder is 0.5% to 15% by mass, and 
 an amount of the conductive material is 0.5% to 5% by mass. 
 
     
     
       15. The method according to  claim 1 , wherein the secondary neutralized slurry is recirculated to the dispersing and mixing apparatus to be used in the neutralizing step.